It is planned, by objective testing, to study the skeletal muscle circulation in the extremities of symptomatic and asymptomatic patients with lipoprotein abnormalities. Appropriate chemical, electrophoretic, ultracentrifugal, or immunological blood studies will determine selection of the patients to be included in the investigation. Blood and plasma viscosity studies will also be performed. After selection and grouping into hyperlipoproteinemic types, blood flow will be studied by radioisotope disappearance rates from local depots during exercise and after an ischemic-exercise stimulus, and by venous occlusion plethysmography measurements of post-occlusion reactive hyperemia. Patients demonstrating an abnornmal circulatory response will then be in treatment groups or control groups. The treatment groups will be maintained on appropriate antilipemic diets and restudied at 3 month intervals. If the lipid abnormalities are not corrected, an antilipemic drug will be added to the diet for the next three months and the studies repeated. Control group patients will be similarly studied but will receive a normal diet and placebo capsules when indicated. Patients will continue to be restudied for a 5 year period. This study should determine objectively whether correction of lipoprotein abnormalities has a beneficial effect on the circulatory impairment in these patients, either by halting or reversing the arteriosclerotic process in the blood vessels or by a change in blood viscosity.